The heart is a hollow muscle which by its rhythmic contraction ensures movement of the blood through the vessels. It comprises four chambers: the right atrium and the left atrium arranged in the upper part of the heart; the right ventricle and the left ventricle arranged in the lower part.
The right ventricle is intended to receive the blood coming from the right atrium and then eject it into the pulmonary artery. This constitutes the “pulmonary circulation” for sending the blood to the lungs to be reoxygenated.
The left ventricle receives the oxygenated blood from the lungs via the left atrium and then ejects it into the aorta for carrying oxygen to all the tissues of the body. This is the “major circulation”, known as the systemic circulation.
Cardiac insufficiency (CI), a progressive inability of the heart to supply a sufficient blood flow to meet an individual's metabolic needs in everyday life, is the second commonest cause of death in Western countries. Treatment of cardiac insufficiency, which consists of increasing the blood flow in a manner appropriate to the needs of the patient, is not very effective with existing techniques, and is extremely costly.
Document US2009/0024212 is known, describing a pump for treating cardiac insufficiency due to inactivity of the sigmoid valves of the heart. This pump is of an elongated shape extending from the interior of the left ventricle to the interior of the aorta so as to replace the function of the valves.
Document U.S. Pat. No. 6,217,541 is also known, describing a heart pump which is also inserted through the aorta and into the ventricle. The end of the pump aspirates the blood contained in the left ventricle and then transfers it to the aorta via a flexible tube integral with the end of the pump and arranged through the valves.
The pumps described above require extremely complex fitting, and are not intended for permanent use.
Document U.S. Pat. No. 6,234,772 is also known, describing an implantable rotary pump. This pump is of the magnetic drive type and makes it possible to force the circulation of the blood while avoiding any stagnant area. This document says nothing regarding any effective fitting of the pump.
Document WO2010/010407 describes a cardiac assist rotary pump propelling blood from the left ventricle through the aortic valve. This pump is fixed through the aortic valve with fixing means in the aorta and at the ventricular apex. The electric motor is located in the conduit passing through the aortic valve.
Finally, document US2005/0107657 is known, describing a left ventricular assist pump (mixed-flow blood pump) with a so-called “radial” circuit for admission of the blood and a so-called “axial” circuit for ejection of the blood by means of a rotary propelling unit located at the centre of the device. The base is held within the left ventricular cavity by a semi-rigid rod through the apex of the ventricle, whereas the top of the device passes through the aortic valve with modification or functional suppression of this valve. Surgically, sternotomy with establishment of extracorporeal circulation is necessary, as an incision must be made at the root of the aorta. This document further discloses an equation of optimum efficiency between the diameter of the pump and the number of revolutions per minute of the propelling unit (up to 11,000 rpm). The diameter of the pump is given as ˜20-22 mm.